1. Field of the Invention
The present invention relates to a zoom lens system, and more particularly, to a light-weight zoom lens system used in cameras.
2. Description of the Related Art
Traditionally, a zoom lens system widely used in digital cameras includes a first lens group with negative optical power, a second lens group with positive optical power, and a third lens group with positive optical power, arranged in order from an object side to an image side.
In recent years, due to remarkable development in digital cameras, the trend of digital cameras is moving toward a small and thin size and light weight. In addition, for photo elements used in digital cameras, such as a charge-coupled Device (CCD), the trend is moving toward higher resolution. Accordingly, a zoom lens system, disclosed in JP Patent Application No. 2000-284177, utilizes a third lens group to rapidly focus and attain a clearer image and to modify its optical aberrations.
Nevertheless, the demand for an increasing of pixels as well as smaller size of each pixel for cameras makes modifying the spherical aberration more urgently necessary. Further, the zoom lens system disclosed in JP Patent No. 2000-284177 fails to modify spherical aberration to satisfy current standards.